1. Field of the Invention
The present invention relates to an apparatus for driving a solid-state image pickup device suitable for optimizing the timing for transmission of a drive signal to be supplied to a solid state image pickup element for adjusting the timing for performing a sample-and-hold operation on an output signal from a device such as a solid-state image pickup element.
2. Description of the Prior Art
FIG. 1 is a block diagram showing prior art apparatus for driving a solid-state image pickup device disclosed, for example, in Japanese Laid-open Patent Publication No. 63-1263. Referring to the figure, reference numeral 1 denotes a solid-state image pickup element for converting a light image incident on its element surface through a lens 2 into an electric signal to be output therefrom, 3 denotes a video signal processing circuit for performing such a process as sample and hold on an output signal from the solid-state image pickup element 1 to obtain a continuous signal and converting the obtained signal into an ordinary video signal to be output therefrom, 4 denotes a pulse generator for generating pulse signals such as that which derives the solid-state image pickup element 1, 6 and 7 denote delay lines for adjusting the timing of the drive signals from the pulse generator 4, 8 and 9 denote drivers for output pulses from the delay lines 6, 7, respectively, 11 and 12 denote pulse drivers for amplifying signals from the pulse generator 4 and delivering the amplified signals to the solid-state image pickup element 1, 10 denotes a buffer amplifier for amplifying a signal output from the solid-state image pickup element 1, in response to the driving signal from the pulse generator 4 passed through the pulse drivers 11, 12 and driving signals from the drivers 8, 9, and supplying the amplified signal to the video signal processing circuit 3, and 5 denotes a monitor television for displaying a video signal from the video signal processing circuit 3.
Operation of the described arrangement will be described below.
The lens 2 focuses an image of an object, not shown, on the element surface of the solid-state image pickup element 1 and this light image is converted into electric charges to be accumulated within the solid-state image pickup element 1. The accumulated charges are transferred to shift register, not shown, within the solid-state image pickup element 1 responding to driving signals generated by the pulse generator 4 and supplied thereto through the pulse drivers 11, 12, and these charges are read to the outside being converted into a voltage signal in synchronism with driving signals generated by the pulse generator 4, subjected to delay adjustments in the delay lines 6, 7, and supplied thereto through the drivers 8, 9. The signal read out of the solid-state image pickup element 1 is input through the buffer amplifier 10 to the video signal processing circuit 3, and therein, the signal is subjected to such processes as sample and hold to be converted into a continuous signal and then into an ordinary video signal. The thus obtained video signal is output to the monitor television 5 and displayed as a video image for viewing.
Since the prior art apparatus for driving solid-state image pickup device is arranged as described above, in order to adjustment the timing for the sample-and-hold process of the signal read out form the solid-state image pickup element 1, it is practiced, in the delay lines 6, 7, to delay and adjust the timing of the driving signals for the signal reading supplied from the pulse generator 4 to the solid-state image pickup element 1. However, since the delay lines 6, 7 are elements being rather expensive, and further, peripheral circuits such as a TTL interface are required for the driving, there have been such problems that the circuit becomes large in scale and requires a large mount space, and further, it is difficult to make delicate timing adjustments since the adjustable range of the delay time is small.